scope:

This Recommendation defines parameters that may be used in specifying and assessing the performance of speed, accuracy, dependability and availability of IP packet transfer of international Internet Protocol (IP) data communication services. The defined parameters apply to the end-to-end, point-to-point IP service and to the network portions that provide, or contribute to the provision of, such service in accordance with the normative references specified in clause 2. Connectionless transport is a distinguishing aspect of the IP service that is considered in this Recommendation.

For the purpose of this Recommendation, end-to-end IP service refers to the transfer of user-generated IP datagrams (referred to in this Recommendation as IP packets) between two end hosts as specified by their complete IP addresses. This differs from the boundaries implied by the phrase "end-to-end" in some other Recommendations. For example, [ITU-T P.10] defines end-to-end quality as related to the performance of a communication system, including all terminal equipment. For voice services, end-to-end is equivalent to mouth-to-ear quality.

NOTE 1 - This Recommendation defines parameters that can be used to characterize IP service provided using Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6); applicability or extension of this Recommendation to other protocols (e.g., resource reservation protocol (RSVP)) is for further study.

NOTE 2 - Recommendations for the performance of point-to-multipoint IP service are currently under development.

The ITU-T Y.1540 performance parameters are intended to be used in planning and offering international IP service. The intended users of this Recommendation include IP service providers, equipment manufacturers and end users. This Recommendation may be used by service providers in the planning, development and assessment of IP service that meets user performance needs; by equipment manufacturers as performance information that will affect equipment design; and by end users in evaluating IP service performance.

The scope of this Recommendation is summarized in Figure 1. The IP service performance parameters are defined on the basis of IP packet transfer reference events (IPREs) that may be observed at measurement points (MPs) associated with specified functional and jurisdictional boundaries. For comparability and completeness, IP service performance is considered in the context of the 3x3 performance matrix defined in [ITU-T I.350]. Three protocol-independent communication functions are identified in the matrix: access, user information transfer and disengagement. Each function is considered with respect to three general performance concerns (or "performance criteria"): speed, accuracy and dependability. An associated two-state model provides a basis for describing IP service availability.

NOTE 3 - In this Recommendation, the user information transfer function illustrated in Figure 1 refers to the attempted transfer of any IP packet, regardless of its type or contents.